Machine That "Says When"

Evening Post, Volume CXVI, Issue 103, 28 October 1933, Page 23

Machine That "Says When"

A'machine that will "say when" in any circumstances has been produced at the National Physical Laboratory, Teddirigton, under the Department of Scientific and Industrial Eescarch, says tho "Morning Post." It is worked by a photo-electric coll on the same principle- as the famous "invisible ray." The uses to which it could bo put aro almost unlimited. Among them are: ! Tho control of theatre and other queues by such announcements as "First five rows full," "Last twenty seats," and "Houso full," the latter to be followed after a warning light' by tho automatic closing of the doors; the measurement of engine speeds up to tho highest speeds available; and tho control of factory production by cutting off conveyor belt supplies when any specified number of packages has been delivered. " All these achievements and many others are made possible by the fact that the machine can be set in advance to count up to any desired num ber and then "trained" to take whatever action is appropriate in tho particular circumstances. Yet its original purpose was nothing more spectacular than to provide a more economical method of measuring the performance of new types of domestic electricity supply meters when various "loads" of current woro being taken from the mains. The old method of timing the usual slowly revolving disc with a stopwatch, it was explained, involved tho attendance of two trained workers if accurate results were to bo secured..-A one-man test was desired —and this is what the laboratory devised. A small mirror was placed on tho revolving tlise. A fixed beam of light was shone in the direction of the mirror^ and a photo-electiie cell jvas

so placed that once every revolution the reflected light shone-, upon it. The effect of this was to provide an. electrical record of each revolution without touching or in any way interfering with the revolving wheel. Next, part of the mechanism of an automatic telephone exchange was pressed into service. This is the device by which vacant circuits between any two exchanges arc automatically selected as soon as the caller has finished dialling the exchange wanted. This has been adapted to do the work of counting1. It can be pre-set to any desired figure. The -stop-watch ia started when tho first signal is-re-ceived from tho photo-oleotfic cell, and it is stopped again at the- precise fraction of a second when. , the count-is finished. For direct counting—-whether of the revolutions of a wheel, of people passing through a door, or of anything sufficiently solid to block the light'ray— the machine will work up to; 3000 events a minute. But tho robot can also be adjusted to record only every tenth or hundredth interruption of the light ray, and in this way it can be snade to work up to tho very highest speeds—for examplo, in the testing of high-speed engines. Equally it would count SUch relatively slow events as the lapping of a car round a racing track. Over and above timing, the robot counter could be made to do anything of which olectrical relays are capable. It could turn on lights, shut doors, release a "cannod voice," start or stop machinery, and even operate a lottery by giving free gifts to every hundredth caller. Meantime the National Physical Laboratory has simplified an important part of its routine work—and there is Batisfactiou at